Koper in Winter
In winter (December, January and February), Koper sees average daytime highs around 8°C and overnight lows near 3°C, with 274 mm of precipitation over about 28 wet days across the season. It is the coldest season of the year and the 3rd-wettest season.
Across winter, daytime highs hold fairly steady around 8°C. The sky is clear or mostly clear about 36% of the time across winter, and the air most often feels dry.
Winter is Koper's weakest season of the year to visit on our travel score. For the whole year in context, see Koper's year-round climate.
- Avg daytime high
- 8°C
- coldest season of the year
- Avg overnight low
- 3°C
- Precipitation
- 274 mm
- 28 wet days
- Avg wind
- 11 km/h
- Travel score
- 1.4
- weakest season of the year
- Months
- Dec · Jan · Feb
Temperature in Koper in Winter
Across winter, daytime highs hold fairly steady around 8°C.
A typical winter day in Koper reaches about 8°C and drops to 3°C overnight. The warmest of the three months is February, the coolest January.
How winter really feels in Koper
Once humidity and wind are folded in, winter brings about 0 days that feel above 32°C and 35 that feel at or below 0°C.
The story in winter is cold — wind chill drags the overnight "feels like" below the raw low.
Koper weather by month
How the three winter months (December, January and February) compare with the rest of the year — the season's months are highlighted.
| Month | High / Low (°C) | Rainfall (mm) | Wet days | Snow days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|---|
| Jan | 7° / 3° | 77 | 9.1 | 0.9 | 8.9 | 1.1 |
| Feb | 9° / 3° | 85 | 8.5 | 1.5 | 10.1 | 1.6 |
| Mar | 12° / 6° | 86 | 9.3 | 0.7 | 11.6 | 3.3 |
| Apr | 16° / 9° | 95 | 11.2 | 0.2 | 13.2 | 4.8 |
| May | 20° / 14° | 103 | 11.7 | 0 | 14.7 | 6.2 |
| Jun | 24° / 18° | 85 | 10.1 | 0 | 15.4 | 7.0 |
| Jul | 27° / 20° | 62 | 8.2 | 0 | 15.1 | 7.2 |
| Aug | 27° / 20° | 89 | 8.5 | 0 | 13.9 | 7.1 |
| Sep | 22° / 16° | 147 | 10.3 | 0 | 12.3 | 6.8 |
| Oct | 18° / 12° | 157 | 12.2 | 0 | 10.7 | 5.5 |
| Nov | 12° / 8° | 167 | 12.7 | 0.3 | 9.3 | 3.1 |
| Dec | 8° / 4° | 112 | 9.9 | 0.9 | 8.6 | 1.5 |
Cloud cover in Winter
The sky is clear or mostly clear about 36% of the time across winter.
Chance of precipitation in Winter
Koper gets around 274 mm of rain and snow over 28 wet days across winter. The line is the day-by-day chance of measurable precipitation.
Humidity in Winter
Most of winter feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Winter
Winds average 11 km/h across winter.
Sunrise & sunset in Winter
Daylight runs from about 8 h 48 min in early December to 10 h 42 min by late February. The lit band spans sunrise to sunset each day.
Solar energy in Winter
Average shortwave solar energy reaching the ground each day across winter, about 1.7 kWh/m².
Is winter a good time to visit Koper?
Our two travel scores rate winter for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.
winter is a weaker month for outdoor sightseeing in Koper.
What to pack for Koper in Winter
From winter's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In winter, Koper sees daytime highs around 8°C and nights near 3°C. Pack a warm layer. Worth having: a heavy coat and rain gear. About 28 days see rain.
Sea temperature near Koper in Winter
The nearest coast averages about 11°C across winter — the other half of the beach question. The full-year curve and swim-comfort zones are below.
The sea offshore is warmest in August at about 25°C and coldest in February near 10°C.
It's comfortable for a long swim from May 31 to Oct 9 — about 4.3 months when the water holds above 20°C.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°C) | 11 | 10 | 10 | 13 | 18 | 23 | 25 | 25 | 23 | 19 | 16 | 13 |
| Comfort | Bracing | Bracing | Bracing | Bracing | Cool | Refreshing | Warm | Warm | Refreshing | Cool | Cool | Bracing |
| Sea temperature (°C) | Comfort | |
|---|---|---|
| Jan | 11 | Bracing |
| Feb | 10 | Bracing |
| Mar | 10 | Bracing |
| Apr | 13 | Bracing |
| May | 18 | Cool |
| Jun | 23 | Refreshing |
| Jul | 25 | Warm |
| Aug | 25 | Warm |
| Sep | 23 | Refreshing |
| Oct | 19 | Cool |
| Nov | 16 | Cool |
| Dec | 13 | Bracing |
UV index in Koper in Winter
Clear-sky midday UV across winter averages around 1. The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Koper peaks around July 15 at about 8 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near January 1 at about 1 (low).
The index reaches 3 or more — the level where the WHO recommends sun protection — in 7 months of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 1 | 2 | 4 | 7 | 7 | 8 | 8 | 7 | 5 | 3 | 2 | 1 |
| Level | Low | Moderate | Moderate | High | High | Very high | Very high | Very high | Moderate | Moderate | Low | Low |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 1 | Low |
| Feb | 2 | Moderate |
| Mar | 4 | Moderate |
| Apr | 7 | High |
| May | 7 | High |
| Jun | 8 | Very high |
| Jul | 8 | Very high |
| Aug | 7 | Very high |
| Sep | 5 | Moderate |
| Oct | 3 | Moderate |
| Nov | 2 | Low |
| Dec | 1 | Low |
Air quality in Koper in Winter
Average fine-particle pollution (PM2.5) through the year — so you can see where winter falls, not just the annual average.
Air quality in Koper is worst in January — around 22 µg/m³ PM2.5 (moderate), about 1.8× the cleanest month (September, 12 µg/m³).
Modeled monthly averages (CAMS reanalysis, 2015–2024).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PM2.5 (µg/m³) | 22 | 20 | 20 | 19 | 16 | 16 | 16 | 13 | 12 | 14 | 14 | 18 |
| Level | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 22 | Moderate |
| Feb | 20 | Moderate |
| Mar | 20 | Moderate |
| Apr | 19 | Moderate |
| May | 16 | Moderate |
| Jun | 16 | Moderate |
| Jul | 16 | Moderate |
| Aug | 13 | Moderate |
| Sep | 12 | Moderate |
| Oct | 14 | Moderate |
| Nov | 14 | Moderate |
| Dec | 18 | Moderate |
Where is Koper?
Koper sits at 45.5°N, 13.7°E, 12 m above sea level, in Slovenia. The nearest listed city is Trieste, 12 km away.
Topography around Koper
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Koper.
Within 3 km, the terrain around Koper has only modest variations in elevation — a maximum elevation change of 238 m around an average of 24 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 575 m; within 80 km, very significant variations in elevation — a maximum elevation change of 2,150 m.
The land around Koper is covered by water (34%) and artificial surfaces (23%) within 3 km, trees (46%) and water (34%) within 16 km, and trees (48%) and water (29%) within 80 km.
Slovenia travel facts
- Travel advisory
- Level 1
- Exercise Normal Precautions
- Power plugs
- Type C / F
- 230 V · 50 Hz
- Prices
- ≈ 63% of US
- price level, 2025
- GDP per capita
- $37,376
- 2025
- Happiness
- 6.9 / 10
- World Happiness, 2025
- Safe drinking water
- 100%
- of population, 2024
- Homicide rate
- 0.6
- per 100k, 2023
- Road deaths
- 5.1
- per 100k/yr, 2019
- Income group
- High
- World Bank
- Religion
Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.
Data sources
Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Koper (45.5482°, 13.7296°, elevation 12 m), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google.